Up to date, the secure transmission distance of MDI-QKD has been extended up to more than four hundred kilometres [1]} which shows great advantages in long-distance communication. However, its key rate is still seriously affected by the finite-size effect, and the block size used for considering finite-size effects is usually larger than \( 10^{12} \)  [1]}, [3]}. Fortunately, the 4-intensity MDI-QKD protocol [4]} and the double-scanning method [5]} have been invented and dramatically improve the performance of the MDI-QKD. Based on the above theoretical work, we carry out a proof-of-principle experimental demonstration, and mainly focus on the situation with a small data size, i.e., \( 10^{10} \)  pulses are emitted and 150 km transmission distance is successfully achieved.
